Here's one I heard during a trip to Arkansas once. I'd have to confirm it, but it sounds reasonable.

If you look at the left (western) edge of the state, you'll notice there's a diagonal part, and then a jog where it goes more or less vertical.
While mapping out the state, the surveyors were OFF on the western boundary (I can't say I remember why, now), but rather than go back and correct it, they just paid off a few of the Native American tribes for the encroachment into "Indian Territory." Otherwise the western edge should have been one straight, continuous latitude line.

#1476